Developmental Biology Commons^™

Molecular Mechanisms Regulating Neonatal Oocyte Survival And Primordial Follicle Formation In The Mouse Ovary, Robin L. Jones

Biology - Dissertations

In mammals, formation of the primordial follicle is a complex process involving the breakdown of germ cell cysts, where oocytes must separate from each other and subsequently become surrounded by somatic cells. As cysts separate, a large number of germ cells are lost by apoptosis, however the mechanisms by which cyst breakdown and germ cell death occur are not well understood. We first hypothesized that two anti-apoptotic regulators from the BCL2 family of proteins, BCL2 and MCL1, may be responsible for regulating neonatal oocyte survival. To elucidate the effects of BCL2 in the neonatal ovary, we examined ovaries of both …

Genetic Analysis Of The Hippo Pathway In Mouse Liver, Li Lu

Dissertations and Theses (Open Access)

Cancer therapy and tumor treatment remain unsolved puzzles. Genetic screening for tumor suppressor genes in Drosophila revealed the Hippo-signaling pathway as a kinase cascade consisting of five core components. Disrupting the pathway by deleting the main component genes breaks the balance of cell proliferation and apoptosis and results in epithelial tissue tumorigenesis. The pathway is therefore believed to be a tumor suppressor pathway. However, a corresponding role in mammals is yet to be determined. Our lab began to investigate the tumor suppression function of the potent mammalian Hippo pathway by putting floxed alleles into the mouse genome flanking the functional-domain-expressing …

Phenotypic Plasticity Of Rattlesnake Trophic Morphology, Matthew Thomas Smith

Graduate Theses and Dissertations

The trophic morphology of gape-limited predators constrains the shape and size of prey items they can ingest. Trophic morphology consists of any morphological feature that is involved in the handling and ingestion of food. Diet has a profound effect on the morphology of many gape-limited predators. Identifying how prey type and resource level affect the morphology of different populations is an essential step in understanding the mechanisms contributing to patterns of morphological diversity. Species interactions (Chapter 1) induce plasticity in morphology that can lead to increased fitness, morphological divergence, and eventually speciation.

In Chapter 2, a laboratory study tested the …

Cartilage On The Move: Cartilage Lineage Tracing During Tadpole Metamorphosis, Ryan R. Kerney, Alison L. Brittain, Brian K. Hall, Daniel R. Buchholz

Biology Faculty Publications

The reorganization of cranial cartilages during tadpole metamorphosis is a set of complex processes. The fates of larval cartilage-forming cells (chondrocytes) and sources of adult chondrocytes are largely unknown. Individual larval cranial cartilages may either degenerate or remodel, while many adult cartilages appear to form de novo during metamorphosis. Determining the extent to which adult chondrocytes/cartilages are derived from larval chondrocytes during metamorphosis requires new techniques in chondrocyte lineage tracing. We have developed two transgenic systems to label cartilage cells throughout the body with fluorescent proteins. One system strongly labels early tadpole cartilages only. The other system inducibly labels forming …

Rapid Range Expansion In The Great Plains Narrow-Mouthed Toad (Gastrophryne Olivacea) And A Revised Taxonomy For North American Microhylids, Jeffrey W. Streicher, Christian L. Cox, Jonathan A. Campbell, Eric N. Smith, Rafael O. De Sá

Biology Faculty Publications

We investigated genetic variation within the Great Plains narrow-mouthed toad, Gastrophryne olivacea, across its geographic range in the United States and Mexico. An analysis of mitochondrial DNA (mtDNA) from 105 frogs revealed remarkably low levels of genetic diversity in individuals inhabiting the central United States and northern Mexico. We found that this widespread matrilineal lineage is divergent (ca. 2% in mtDNA) from haplotypes that originate from the western United States and western coast of Mexico. Using a dataset that included all five species of Gastrophryne and both species of the closely related genus Hypopachus, we investigated the phylogenetic …

Sex Determination In Beetles: Production Of All Male Progeny By Parental Rnai Knockdown Of Transformer, Jayendra Nath Shukla, Subba Reddy Palli

Entomology Faculty Publications

Sex in insects is determined by a cascade of regulators ultimately controlling sex-specific splicing of a transcription factor, Doublesex (Dsx). We recently identified homolog of dsx in the red flour beetle, Tribolium castaneum (Tcdsx). Here, we report on the identification and characterization of a regulator of Tcdsx splicing in T. castaneum. Two male-specific and one female-specific isoforms of T. castaneum transformer (Tctra) were identified. RNA interference-aided knockdown of Tctra in pupa or adults caused a change in sex from females to males by diverting the splicing of Tcdsx pre-mRNA to male-specific isoform. All the pupa and adults developed from Tctra …

Developing Monitoring Methods For Leptasterias Spp. As Sentinel Species In Detecting Local Environmental Changes, Zachary Sturbaum, Kathryn Nuessly, Riley J. Smith, C. Sarah Cohen

STAR Program Research Presentations

Leptasterias spp., a six-rayed sea star, is found in rocky intertidal habitats ranging from Alaska to central California. Leptasterias spp. can be monitored on a broad scale throughout their range by a variety of means using timed counts and random plot censusing in order to detect both large-scale and local-level changes in the environment due to climate change, land-based human activity, or other environmental events. Leptasterias brood their young externally until the embryos grow into fully developed juveniles. These juveniles disperse by crawling away, limiting their dispersal potential. This localized dispersal provides an opportunity to use Leptasterias spp …

Next Generation Sequencing Reveals Gene Expression Patterns In The Zebrafish Inner Ear Following Growth Hormone Injection, Gopinath Rajadinakaran

Masters Theses & Specialist Projects

Loss of hair cells due to acoustic trauma results in the loss of hearing. In humans, unlike other vertebrates, the mechanism of hair cell regeneration is not possible. The molecular mechanisms that underlie this regeneration in nonmammalian vertebrates remain elusive. To understand the gene regulation during hair cell regeneration, our previous microarray study on zebrafish inner ears found that growth hormone (GH) was significantly upregulated after noise exposure. In this current study, we utilized Next Generation Sequencing (NGS) to examine the genes and pathways that are significantly regulated in the zebrafish inner ear following sound exposure and GH injection. Four …

Transcriptional Regulation Of Profilin Is Required For Drosophila Larval Wound Closure, Amanda Brock

Dissertations and Theses (Open Access)

Injury is an inevitable part of life, making wound healing essential for survival. In postembryonic skin, wound closure requires that epidermal cells recognize the presence of a gap and change their behavior to migrate across it. In Drosophila larvae, wound closure requires two signaling pathways (the Jun N-terminal kinase (JNK) pathway and the Pvr receptor tyrosine kinase signaling pathway) and regulation of the actin cytoskeleton. In this and other systems, it remains unclear how the signaling pathways that initiate wound closure connect to the actin regulators that help execute wound- induced cell migrations. Here we show that chickadee, which encodes …

Identification And Analysis Of A Novel Role For The To Usled-Like Kinase In Regulating Mitotic Spindle Dynamics, Jason R. Ford

Dissertations and Theses (Open Access)

Deregulation of kinase activity is one example of how cells become cancerous by evading evolutionary constraints. The Tousled kinase (Tsl) was initially identified in Arabidopsis thaliana as a developmentally important kinase. There are two mammalian orthologues of Tsl and one orthologue in C. elegans, TLK-1, which is essential for embryonic viability and germ cell development. Depletion of TLK-1 leads to embryonic arrest large, distended nuclei, and ultimately embryonic lethality. Prior to terminal arrest, TLK-1-depleted embryos undergo aberrant mitoses characterized by poor metaphase chromosome alignment, delayed mitotic progression, lagging chromosomes, and supernumerary centrosomes.

I discovered an unanticipated requirement for TLK-1 …

Delayed Expression Of Cell Cycle Proteins Contributes To Astroglial Scar Formation And Chronic Inflammation After Rat Spinal Cord Contusion, Junfang Wu, Ahdeah Pajoohesh-Ganji, Bogdan A. Stoica, Michael Dinizo, Kelsey Guanciale, Alan I. Faden

Anatomy and Regenerative Biology Faculty Publications

Background

Traumatic spinal cord injury (SCI) induces secondary tissue damage that is associated with astrogliosis and inflammation. We previously reported that acute upregulation of a cluster of cell-cycle-related genes contributes to post-mitotic cell death and secondary damage after SCI. However, it remains unclear whether cell cycle activation continues more chronically and contributes to more delayed glial change. Here we examined expression of cell cycle-related proteins up to 4 months following SCI, as well as the effects of the selective cyclin-dependent kinase (CDKs) inhibitor CR8, on astrogliosis and microglial activation in a rat SCI contusion model.

Methods

Adult male rats were …

Role Of Progesterone Receptors In Neonatal Ovary Development, Marta N. Dzyadyk

Renée Crown University Honors Thesis Projects - All

In female mammals, proper oocyte development is a vital prerequisite for future gamete viability and fertility. This development of oocytes, known as oogenesis, begins with the migration of primordial germ cells to the genital ridge of the early embryo, where multiple rounds of mitotic division occur without complete cytokinesis. The result is temporary cyst morphology. Cyst breakdown is a crucial process in the next developmental stage, resulting in formation of the single oocytes which will grow in follicles surrounded by granulosa cells and eventually develop into eggs. These aspects of embryogenesis are conserved across multiple species, including Drosophila, mice, and …

Analyzing The Roles Of Scl And Gata3 In Zebrafish Spinal Cord Interneuron Specification And Function, Kadiah Oyah Kamara

Renée Crown University Honors Thesis Projects - All

My project focuses on the V2 cells of the zebrafish spinal cord. The V2 cells are an unusual class of spinal cells because they all originate from molecularly indistinguishable p2 progenitor cells in the spinal cord. However, as these cells become post-mitotic and differentiate, they start to express different transcription factor genes that allow them to initially develop into two sets of molecularly distinct cells. As differentiation continues, at least one more class of molecularly distinct cells develops. Just as in other vertebrates, in zebrafish the V2 cells differentiate into at least two functionally distinct classes of cells, specifically, the …

Specification Of The Neural Crest-Derived Pharyngeal Mesenchyme: The Role Of Pharyngeal Endoderm, Fgf And Bmp Signaling In The Establishment Of Prechondrogenic Identity And Initiation Of Chondrogenesis., Megha Kumar

All Dissertations

This study investigates the role of pharyngeal endoderm in the specification of prechondrogenic identity and initiation of chondrogenesis in the proximal mesenchyme of the second pharyngeal arch. The results show that pharyngeal endoderm is sufficient but not necessary for specification of prechondrogenic identity in the cranial neural crest derived arch mesenchyme. A number of Fgf genes - Fgf3, 4, 8 and 19 are expressed in the pharyngeal endoderm. Further, FGF signaling is sufficient and required for the specification of prechondrogenic identity, marked by Sox9 expression. However, FGF signaling is unable to maintain the Sox9 expression and initiate the chondrogenic program. …

Genetic Identification Of Development Pathways Regulated By Conserved Micrornas In Caenorhabditis Elegans, John L. Brenner

Dissertations (1934 -)

microRNAs (miRNAs) are approximately 22 nucleotide non-coding RNAs that function to repress genes by binding to complementary sites in target mRNAs and play critical roles in development and disease. It is predicted that more than 60% of human genes are regulated by miRNAs, however, little is known about the individual functions of miRNAs. I used the nematode worm, Caenorhabditis elegans, as a model to identify developmental processes and pathways regulated by conserved miRNAs. Genetic examination of miRNA function is hindered by lack of obvious phenotypes attributed to loss of individual miRNA genes. Phenotypes attributable to loss of individual miRNA genes …

Expression Of 14-3-3 Protein Isoforms In Mouse Oocytes, Eggs And Ovarian Follicular Development, Santanu De, Jennifer Marcinkiewicz, Srinivasan Vijayaraghavan, Douglas Kline

Biology Faculty Articles

Background

The 14-3-3 (YWHA) proteins are a highly conserved, ubiquitously expressed family of proteins. Seven mammalian isoforms of 14-3-3 are known (β, γ, ε, ζ, η, τ and, σ). These proteins associate with many intracellular proteins involved in a variety of cellular processes including regulation of the cell cycle, metabolism and protein trafficking. We are particularly interested in the role of 14-3-3 in meiosis in mammalian eggs and the role 14-3-3 proteins may play in ovarian function. Therefore, we examined the expression of 14-3-3 proteins in mouse oocyte and egg extracts by Western blotting after polyacrylamide gel electrophoresis, viewed fixed …

Basic Concepts In Understanding Recovery Of Function In Vestibular Reflex Networks During Vestibular Compensation, Kenna D. Peusner, Mei Shao, Rebecca Reddaway, June C. Hirsch

Anatomy and Regenerative Biology Faculty Publications

Unilateral peripheral vestibular lesions produce a syndrome of oculomotor and postural deficits with the symptoms at rest, the static symptoms, partially or completely normalizing shortly after the lesion due to a process known as vestibular compensation. The symptoms are thought to result from changes in the activity of vestibular sensorimotor reflexes. Since the vestibular nuclei must be intact for recovery to occur, many investigations have focused on studying these neurons after lesions. At present, the neuronal plasticity underlying early recovery from the static symptoms is not fully understood. Here we propose that knowledge of the reflex identity and input–output connections …

Elucidating The Role Of Bone Morphogenetic Proteins And B-Lymphocyte Maturation Protein 1 During Primordial Germ Cell Specification, Laughing Bear Torrez Dulgeroff

Theses Digitization Project

This study will present an optimized protocol to induce and isolate primordial germ cells (PGC) from hESC and hiPSC. Human embrionic stem cells (hESC and induced pluripotent stem cells (iPSC) provide a model for studying paradigms of early development.

Elucidating The Effects Of Tobacco Products On Skeletal Development, Nicole Renee Sparks

Theses Digitization Project

The overall goal of this thesis project is to characterize the molecular mechanisms of tobacco product induced skeletal teratogenicity.

Limb Bone Geometry And Skeletal Physiology In Mice Bred For High Levels Of Activity, Brittney Racheal Coats

Theses Digitization Project

The studies presented here evaluate the effects of exercise and genetics on biomechanically important traits and the skeletal system's role in maintaining proper metabolic health. The goal of the project presented here is to further our understanding of the leptin-bone-insulin pathway and relevant changes that may occur in this pathway as a result of exercise. Cross-sectional analyses of HR mice and control mice allowed or denied wheel access for 10 weeks, revealed significant differences in biomechanical properties.